Magnifier

ABSTRACT

A magnifier for relative apertures exceeding f/1, an angular field larger than 2 X 25* and a pupil distance larger than 0.9 for viewing the anode screen of an image intensifier tube, which forms part of a viewing device, which is mounted in a vehicle.

' United Stat Versteeg UN W] MAGNIFIER Inventor: Frits Johan Versteeg,Rotterdam,

Netherlands Assignee: N. V. Optische lndustrie, de Oude Delft, Delft,Netherlands Filed: Dec. 8, 1972 Appl. No.: 313,331

Foreign Application Priority Data Jan. I4, 1972 Netherlands 7200567 US.Cl. 350/216, 350/175 E, 350/176 Int. Cl. G02b 25/04 Field of Search350/175 E, 216, 220

d d d d d d 7 3,823,999 M/ [451 July16, 1974 [56] References CitedUNITED STATES PATENTS 3,233.5!3. 2/l966 Wagner et al. 350/220 3,6l2,66210/197] Sissel 350/175 E 3,658,4l2 4/1972 Seaman 350/220 PrimaryExaminer-John K. Corbin Attorney, Agent, or Firm-Arthur B. Colvin [57]ABSTRACT A magnifier for relative apertures exceeding f/l. an angularfield larger than 2 X 25 and a pupil distance larger than 0.9 forviewing the anode screen of an image intensifier tube, which forms partof a viewing device, which is mounted in a vehicle.

3 Claims, 8 Drawing Figures PATENTEU I 51974 SHEET 1 0F 2 F|G.2 FIG.3

The invention relates to a magnifier with a relative aperture exceedingf/ 1, an angular field larger than 2 X 15, a pupil distance larger than0.9f, made up of the following components;

A first component made up of a positive front lens having the form of ameniscus;

A second component made up of a single positive power of the rearmostsurface of the fourth component having a value between 0.63/f andl.03/f, and the power of the front surface of the fourth componenthaving a value between 0.5 l/f and 0.63/f.

FIG. I shows an embodiment of the magnifier in accordance with theinvention;

FIGS. 2-4 show aberration curves of the magnifier shown in FIG. 1;

FIG. 5 shows another embodiment of the magnifier lens; according to theinvention; A third component made up ofa single positive lens; GS. hoaberration curves of the magnifier shown in FIG. 5.

A fourth component made up of a lens having the The magnifier shown inFIG. 1 has a pupil distance form of a meniscus with a cemented surface,the of 1.35) and is characterized by the following data, the concavesurface of which being placed in the direcl5 lenses of the magnifierI-VII starting from the front lens tion of the eye. being indicated inthe first column, the refractive indi- A magnifier built in accordancewith the above conces n,n of the glasses of the successive lenses be1ngditions is known from German Auslegeschrift Pat. No. indicated n theSecond Column, the Abbe numbers 1,237,355. A magnifier of this type isused for instance rvu 0f the glasses of the Successive lenses beingindiin viewing of the anode screen of an i age i t ifi cated in thethird column, the successive axial thicktube, which forms part of aviewing devi e, whi h i nesses and separations in air d -d beingindicated in mounted in a vehicle. the fourth column, the radii ofcurvature of the succes- Under these circumstances it is an advantage tohave Sive refractive surfaces rrz' g indicated In the th a pupildistance as large as possible in order to avoid column and the po werArr/r of the successive refractive that the viewer knocks his headagainst the device Surfaces being Indicated the SIXth o n- TABLE I #1f/Q,7 2m=2 30 d,=0.320l r,='1.7541 -0.4s15 1 1.7919 25.8 d,=0.073s

. r,=+9.3903 -0.00s1 11 1.71616 53.8 d -.=O.5l09

r ,=1.2965 +0.5s24 d,=0.0057

. r,=-6.726s 0.1065 111 171616 53.21 d,=0.2720

r ,-2.102o +0.3407 d.,=o.0057

r,,=+5.7902 +0.1237 1v 1.71616 53.x d,=0.3520

r,.=+1.31oo +0.5710 v 1.74795 44.8 d,,=o.6812

r,,=-6.i1029 0.0095 v1 1.81265 25.4 d ,=0.0908

r,,,=+o.9s26 o.s270 d.,=0.3122

r,,=+4.s160 +0.1553 v11 1.74795 44.8 d,,=0.2214

r,,=2.6137 +0.2862 pupil distance d =l.l350

when the vehicle moves in a rough terrain. or on a From the aberrationcurves, shown in FIGS. 2-4, for bumpy road, or that an object ofinterest in the terrain the spherical lateral aberration, theastigmatism and disappears from his field of view. It appears, that thethe distortion respectively it is seen that this magnifier magnifier inaccordance with the German Auslegeshas a good state of correction in anangular field of 2 chrift, having a pupil distance up to 0.85f and alast X 30, the pupil distance of 1.135;" leading to a magnificomponentwith-a concave surface which is turned to cation of 14 times by a realpupil distance of 20 mm. the eye, does not satisfy the requirementsmentioned above under all circumstances. The magnifier as shown in FIG.5 has a pupil distance The object of the invention is to provide amagnifier of 1.0400f and is characterized by the following data, of theabove mentioned type with a relative aperture of the lenses of themagnifier I-VI starting from the front at least f/ l, a pupil distanceof at least 0.9f and an angulens being indicated in the first column,the refractive lar field of at least 2 X 25, and a good state ofcorrecindices n,n of the glasses of the successive lenses tion. beingindicated in the second column, the Abbe num- A magnifier according tothe invention is character- -bers v,-v of the glasses of the successivelenses being ized in that afifth component having the form of aposiindicated in the third column, the successive axial tive lens isplaced behind the fourth component, the thicknesses and separations inair (I -d beingindicated sum of the powers of the two surfaces of thefifth component having a value between 0.35/f and 0.5S/f, the

in the fourth column, the radii of curvature of the successiverefractive surfaces r,-r,, being indicated in the fifth column and thepower An/r of the successive refractive surfaces being indicated in thesixth column.

the powers of the two surfaces of the fifth component having a valuebetween 0.35/f and 0.55/f, the power of nents, a first component made upof a positive front lens having the form of a meniscus, a secondcomponent made up of a single positive lens, a third component made upof a single positive lens, a fourth component made up of a lens havingthe form of a meniscus with a cemented surface, the concave surface ofwhich being placed in the direction of the eye, characterized in that afifth component having the form of a positive lens is placed behind thefourth component, the sum of the rearmost surface of the fourthcomponent having a value between 0.63/f and l.O3/f, and thepower of thefront surface of the fourth component having a value between 0.5 l/f and0.63/f.

2. Magnifier according to claim 1, characterized by the followingnumeral data, the lenses of the magnifier l-VII starting from the frontlens being indicated in the first column, the refractive indices n n ofthe glasses of the successive lenses being indicated in the secondcolumn, the Abbe numbers u n/ of the glasses of the successive lensesbeing indicated in the third column, the successive axial thicknessesand separations in air d,d being indicated in the fourth column, theradii of curvature of the successive refractive surfaces r -r, beingindicated in the fifth column and the power An/r of the successiverefractive surfaces being indicated in the sixth column.

the successive axial thicknesses and separations in air d d beingindicated in the fourth column, the radii of curvature of the successiverefractive surfaces r r being indicated in the fifth column and thepower An/r of the successive refractive surfaces being indicated in thesixth column,

1. Magnifier with a relative aperture exceeding f/1, an angular fieldlarger than 2 X 25*, a pupil distance larger than 0.9f, consisting ofthe following components, a first component made up of a positive frontlens having the form of a meniscus, a second component made up of asingle positive lens, a third component made up of a single positivelens, a fourth component made up of a lens having the form of a meniscuswith a cemented surface, the concave surface of which being placed inthe direction of the eye, characterized in that a fifth component havingthe form of a positive lens is placed behind the fourth component, thesum of the powers of the two surfaces of the fifth component having avalue between 0.35/f and 0.55/f, the power of the rearmost surface ofthe fourth component having a value between 0.63/f and 1.03/f, and thepower of the front surface of the fourth component having a valuebetween 0.51/f and 0.63/f.
 2. Magnifier according to claim 1,characterized by the following numeral data, the lenses of the magnifierI-VII starting from the front lens being indicated in the first column,the refractive indices nI-nVII of the glasses of the successive lensesbeing indicated in the second column, the Abbe numbers Nu I- Nu VII ofthe glasses of the successive lenses being indicated in the thirdcolumn, the successive axial thicknesses and separations in air d1-d12being indicated in the fourth column, the radii of curvature of thesuccessive refractive surfaces r1-r12 being indicated in the fifthcolumn and the power Delta n/r of the successive refractive surfacesbeing indicated in the sixth column,
 3. Magnifier according to claim 1,characterized by the following numeral data, the lenses of the magnifierI-VI starting from the front lens being indicated in the first column,the refractive indices nI-nVI of the glasses of the successive lensesbeing indicated in the second column, the Abbe numbers Nu I- Nu VI ofthe glasses of the successive lenses being indicated in the thirdcolumn, the successive axial thicknesses and separations in air d1-d12being indicated in the fourth column, the radii of curvature of thesuccessive refractive surfaces r1-r11 being indicated in the fifthcolumn and the power Delta n/r of the successive refractive surfacesbeing indicated in the sixth column,